Table 1.
Classification of the LGIC Superfamily.
| Type | Subtypes/Subunits | Main Functions in the CNS | Involvement in CNS Diseases |
|---|---|---|---|
| Anionic Cys-loop receptors | |||
| GABAA | α1–6, β1–3, γ1–3, δ ε π θ | Neuronal hyperpolarization, resulting in inhibitory effect on neuronal activity | Anxiety, insomnia, agitation219 |
| Glycine | α1–4, β | Inhibitory neurotransmission | Hyperekplexia220 |
| Cationic Cys-loop receptors | |||
| Serotonin (5-HT3) | 5-HT3A–E | Modulation of neurotransmitter release in interneurons, regulating the nausea-vomiting system in the CNS | Schizophrenia, addiction, anxiety and cognitive dysfunctions, emesis6,62 |
| Nicotinic acetylcholine receptors (nAChRs) | Muscle type: α1, β1, γ, δ, ε Neuronal type: α2–10, β2–4 |
Large diversity in roles, depending on subtype Mainly regulate presynaptic neurotransmitter release Excitatory postsynaptic potential (muscle type and ganglional), post- and presynaptic excitation Involved in memory and cognitive functions |
Alzheimer’s disease, Parkinson’s disease, epilepsy, schizophrenia, dementia, attention deficit, pain, depression, anxiety, and depression31,59 |
| Zinc-activated ion channel (ZAC) | Function not yet elucidated221 | ||
| Ionotropic glutamate receptors (iGluRs) | |||
| AMPA | GluA1–4 | Fast synaptic transmission, synaptic plasticity | Epilepsy222 |
| Kainate | GluK1–5 | Postsynaptic kainate receptors: excitatory neurotransmission Presynaptic kainate receptors: modulating GABA release |
Epilepsy223 |
| NMDA | GluN1, GluN2A–D, GluN3A–B |
Synaptic plasticity; learning and memory | Alzheimer’s disease, Parkinson’s disease, depression, and schizophrenia224 |
| Orphan | GluD1–2 | Synaptogenesis, synaptic plasticity and motor coordination in cerebellum | Ataxia, dementia, and schizophrenia225 |
| ATP-gated channels | |||
| P2X purinoreceptor | P2X1–7 | Nociception and modulation of synaptic transmission | Chronic pain226 |